This invention relates to automatic control system of a ripper utilized in a civil work which can automatically move the ripper shank in the vertical direction and can control the shank angle to coincide with a preset piercing angle when operating in a piercing operation mode whereas to control the shank angle to coincide with a preset digging angle when operating in a digging operation mode.
Heretobefore, the digging operation by a ripper mounted on the rear end of a civil machine such as a tractor is manually controlled by an operator. Thus, the operator moves the ripper shank in the vertical direction and adjusts the shank angle by experience and by taking into consideration such factors as the ground condition, vehicle speed and other operating conditions. Accordingly, the operator is required to have a high skill and experience. In addition, in order to manually control the ripper shank, the operator must constantly watch the progress of the operation. This not only increases fatigue of the operator but also decreases efficiency of the operation.